The C-LEMMA Memory Interface on the Cray T3D

Christopher D. Walton and Bruce J. McAdam

Abstract:

The challenges associated with the implementation of a
concurrent programming language on a parallel machine are often
independent of the language itself, such as memory-management. This
report is a detailed description of a language-independent
memory-platform for the Cray T3D supercomputer, called the C-LEMMA
interface. The interface is closely based on the definition of the
LEMMA interface used in the DP/ML (Distributed Poly/ML) compiler.
However, the actual implementation is quite different, due to some
severe limitations imposed by the Cray architecture. The
memory-platform provides a distributed shared virtual memory (i.e.
a single shared virtual address space distributed across
processors) with global garbage-collection.

This report is a detailed description of the implementation of
the C-LEMMA interface. It is also intended as a reference manual
for those who wish to implement the run-time system of a concurrent
programming language using the interface.